Regulation of Hypoxia-inducible Factor 1 by Cyclin Dependent Kinases

描述（由申请人提供）：缺氧诱导因子1 （HIF-1）转录因子是细胞对缺氧反应的关键介质。的吗?HIF-1亚基在氧气存在下迅速降解，但在缺氧条件下稳定，并激活促进血管生成、生存、侵袭和葡萄糖代谢的基因转录。HIF-1可以通过基因改变激活，从而增强转录或抑制HIF-1的降解。例如，von Hippel-Lindau （VHL）病使患者易患肾系统侵袭性肿瘤，其特征是HIF-1 γ稳定。HIF-1？驱动这些肿瘤的发展，这些肿瘤是高度血管生成的，对治疗有抵抗力。因此，HIF-1抑制是治疗缺氧和vhl缺陷肿瘤患者的一种有希望的策略。HIF-1的氧依赖性调控？HIF-1的不依赖氧的调控已经得到了很好的研究。还没有完全理解。我们有证据表明HIF-1的稳定性？是由细胞周期蛋白依赖性激酶（CDKs）调控的，特别是CDK1和CDK4。推动这项研究的中心假设是HIF-1？HIF-1的表达受CDKs的调控，确定这种调控的分子机制将产生新的策略来抑制与HIF-1激活相关的肿瘤存活、血管生成和治疗耐药性。我们将通过以下目标来解决这一假设：1]确定CDKs调节HIF-1的机制？表达式。2]检测CDK抑制HIF-1的抗肿瘤效果表达肿瘤，并确定与已批准的抗癌疗法的协同组合。该建议依赖于三种主要方法：1]监测HIF-1在CDK抑制下的表达水平和活性，2]使用质谱法鉴定改变HIF-1的新型翻译后修饰。稳定,

DESCRIPTION (provided by applicant): The hypoxia-inducible factor 1 (HIF-1) transcription factor is a critical mediator of the cellular response to oxygen deprivation. The ? subunits of HIF-1 are rapidly degraded in the presence of oxygen, but are stabilized under hypoxic conditions and activate the transcription of genes that promote angiogenesis, survival, invasion, and glucose metabolism. HIF-1 can be activated by genetic alterations that enhance the transcription or inhibit the degradation of HIF-1?. For example, von Hippel-Lindau (VHL) disease predisposes sufferers to aggressive tumors of the renal system, which are characterized by the stabilization of HIF-1?. The constitutive expression of HIF-1? drives the development of these tumors, which are highly angiogenic and resistant to therapy. Thus, HIF-1 inhibition represents a promising strategy for the treatment of patients with hypoxic and VHL-deficient tumors. While the oxygen-dependent regulation of HIF-1? has been well studied, the oxygen- independent regulation of HIF-1? is not completely understood. We have evidence that the stability of HIF-1? is regulated by cyclin dependent kinases (CDKs), specifically CDK1 and CDK4. The central hypothesis driving this research is that HIF-1? expression is regulated by CDKs, and identification of the molecular mechanisms underlying this regulation will produce novel strategies to inhibit tumor survival, angiogenesis, and therapeutic resistance associated with HIF-1 activation. We will address this hypothesis via the following aims: 1] Identify the mechanism by which CDKs regulate HIF-1? expression. 2] Test the anti-tumor efficacy of CDK inhibition on HIF-1? expressing tumors, and identify synergistic combinations with approved anticancer therapies. This proposal relies on three major approaches: 1] monitoring the expression levels and activity of HIF- 1 in response to CDK inhibition, 2] the use of mass spectrometry to identify of novel post-translational modifications that alter HIF-1? stability, and 3] utilizing CDK inhibitors in HIF-1? expressing tumors in combination with standard therapies. Preliminary data indicate that inhibition of CDK kinase activity significantly decreases the stability of HIF-1? at the protein level. Therefore, we plan to perform mass spectrometry and biochemical analyses to identify novel post-translational modifications on HIF-1? and determine the mechanism through which CDKs regulate HIF-1a expression. Next, we will investigate the efficacy of CDK inhibition as a novel therapeutic approach to target renal tumors that constitutively express HIF-1? due to the loss of VHL. First, in vitro assays will be used to assess the efficacy of CDK inhibitors and identify promising combinations with standard anticancer therapies. Then, in vivo tumor models will serve to determine if CDK-mediated repression of HIF-1? inhibits tumor growth and angiogenesis, and sensitizes HIF-1?-driven tumors to undergo cell death in response to standard therapies. Ultimately, the goal of this proposal is to facilitate the clinical translation of CDK inhibitors for use in tumors with constitutively active IF-1 while also yielding biological information about how HIF-1? stability is regulated by CDKs.